Light-emitting diodes (LEDs) may be used for lighting in portable electronics applications, and the like. It is often desirable to provide a mechanism for adjusting the brightness of the LED. According to a first approach, an LED may be driven with a DC voltage, and the DC voltage may be adjusted to adjust the brightness of the LED. According to a second approach, an LED may be driven with a high peak current having a low duty cycle, and the duty cycle of the current may be adjusted to adjust the brightness of the LED. The second approach consumes less power at a given level of brightness than the first approach.
White LEDs may be used for back-lighting applications. Typically, several white LEDs are coupled in series. A boost switching regulator may be employed to provide a voltage across the white LEDs.